"Cassie" is a song by Christian alternative metal band Flyleaf. It was first released on their self-titled EP Passerby, when they were still named Passerby. "Cassie" subsequently appeared on Flyleaf (EP), Flyleaf LP Sampler, and Flyleaf (album).

The song refers to Lacey Mosley's view on the Columbine High School massacre concerning the death of Cassie Bernall. The account it is based on claims that Cassie Bernall was asked by one of the gunmen whether she believed in God or not. Upon expressing her belief, she was shot in the face. According to some accounts, Cassie was not questioned about her beliefs, but a similar question was put to Valeen Schnurr, who was spared by Dylan Klebold. The investigation team that worked on the Columbine shooting came to similar conclusions regarding the incident and its authenticity. From Wikipedia